TY  - RPRT
TI  - Stopping rules and estimation problems in clinical trials.
AU  - M D Hughes
AU  - S J Pocock
PY  - 1988
DO  - 10.1002/sim.4780071204
UR  - https://pubmed.ncbi.nlm.nih.gov/3231947/
ID  - 3231947
ER  -